Fiber reinforced polymers include a fiber material bound by a matrix, typically provided by a binder, such as a resin. Fiber reinforced polymers are conventionally manufactured using a pultrusion process, an example of which is illustrated in FIG. 1.
In the pultrusion process, incoming fiber 5 is pulled through a production line 10 by a pulling mechanism 15, such as a pair of driven rollers 20. The fiber 5 is drawn into a bath 25 containing one of a variety of binders. Once wetted, the fiber 5 is drawn through a static die 30 that may have one or more heating zones to initiate curing of the binder. In the pultrusion process, the die 30 serves several functions. It creates pressure to promote wetting of the fiber 5, heats the binder and the fiber 5, controls curing of the binder, and controls the final shape of pultruded product.
Binders have curing profiles that are dictated by chemical reactions (curing, crosslinking, drying, etc.). These curing profiles are functions of the chemical reactivity of the binder, process temperature, and dwell time at the process temperature. As production speeds increase, it becomes increasingly difficult to ensure proper curing of the binder.
The conventional pultrusion process illustrated in FIG. 1 has inherent constraints that severely hinder the speed of the process. The length of the die 30 is the primary constraint on the speed of the process, with process temperature, process friction, and process gas removal providing other limiting constraints. The binder bath 25 presents its own drawbacks, including difficulty mixing and maintaining multi-part, reactive binders, undue amounts of waste, and high operating costs due to the typically large volume of binder needed to fill the bath 25. It has previously not been cost-effective to manufacture fiber reinforced products, especially if one or more fast-curing thermosetting polymers and/or a multi-component thermosetting polymer are utilized as a portion of the binder, for at least the reasons listed above.